NFS: Add some new I/O counters for FS-Cache doing things for NFS

Add some new NFS I/O counters for FS-Cache doing things for NFS.  A new line is
emitted into /proc/pid/mountstats if caching is enabled that looks like:

	fsc: <rok> <rfl> <wok> <wfl> <unc>

Where <rok> is the number of pages read successfully from the cache, <rfl> is
the number of failed page reads against the cache, <wok> is the number of
successful page writes to the cache, <wfl> is the number of failed page writes
to the cache, and <unc> is the number of NFS pages that have been disconnected
from the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/nfs/iostat.h b/fs/nfs/iostat.h
index a36952810032..a2ab2529b5ca 100644
--- a/fs/nfs/iostat.h
+++ b/fs/nfs/iostat.h
@@ -16,6 +16,9 @@
 
 struct nfs_iostats {
         unsigned long long      bytes[__NFSIOS_BYTESMAX];
+#ifdef CONFIG_NFS_FSCACHE
+        unsigned long long      fscache[__NFSIOS_FSCACHEMAX];
+#endif
         unsigned long           events[__NFSIOS_COUNTSMAX];
 } ____cacheline_aligned;
 
@@ -57,6 +60,21 @@ static inline void nfs_add_stats(const struct inode *inode,
         nfs_add_server_stats(NFS_SERVER(inode), stat, addend);
 }
 
+#ifdef CONFIG_NFS_FSCACHE
+static inline void nfs_add_fscache_stats(struct inode *inode,
+                                         enum nfs_stat_fscachecounters stat,
+                                         unsigned long addend)
+{
+        struct nfs_iostats *iostats;
+        int cpu;
+
+        cpu = get_cpu();
+        iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
+        iostats->fscache[stat] += addend;
+        put_cpu_no_resched();
+}
+#endif
+
 static inline struct nfs_iostats *nfs_alloc_iostats(void)
 {
         return alloc_percpu(struct nfs_iostats);